Forget about sun damage, vitamine D is good for you. WHat I would worry about is the dirt... think about how dirty your cloths can get in a single day, there would be no barier protecting our skin from the harsh polutants... yuck!
While I do not find nudity offencive (its natural and everyone, even the most obese, is beautiful), I do think people need to show descretion at to the appropriate time to "whip it out." Nudity is considered the norm in all nudist colonies so it looses it's shock value and become almost a liberating experience, But in cultures where nudity only happens behind closed doors I think that policy should be respected and it should be kept that way. For example if one woman were to decide to walk naked down the street she has every right to, but law prohibits it because it is against the norm, unexpected, and dangerous. People may become destracted and cause an accident while staring. An acutal example of this is a billboard that was put up in time square, for Calvin Klein underwear or something, that was so shockingly nude that it caused dozens of accidents before it was ordered to be taken down. In most of our cultures Breasts ad genitalia are private, and I believe in this area it is commendable. Those who want to live nude for any reason other than shock value can find another culture to allign themselves with and live life the way they were born.